Batteries, such as primary alkaline batteries, are commonly used as energy sources. Generally, alkaline batteries include a cathode, an anode, a separator, and an electrolytic solution. The cathode can include, for example, manganese dioxide particles as the active material, carbon particles that enhance the conductivity of the cathode, and a binder. The anode may be, for example, a gel including zinc particles as the active material. The separator is disposed between the cathode and the anode. The electrolytic solution can be, for example, a hydroxide solution that is dispersed throughout the battery.
When a battery is used as an electrical energy source in a device, such as a flashlight or a cellular telephone, electrical contact is made to the anode and the cathode, allowing electrons to flow through the device and permitting the respective oxidation and reduction reactions to occur to provide electrical power. An electrolyte in contact with the anode and the cathode contains ions that flow through the separator between the electrodes to maintain charge balance throughout the battery during discharge. Mercury and other metals such as lead and cadmium often are added to the anode to reduce the levels of hydrogen gas produced during the electrochemical reaction of the battery.